Add two tablespoons of butter to a pan on medium heat.
Once the butter has melted, add your onions and garlic. Cook for about 7 minutes or until soft
Add your tomato paste and mix well. Cook for about 3 minutes.
Add your tomato sauce and balsamic vinegar and cook for 20 minutes on low heat.
Boil your pasta according to package instructions
Once your sauce is ready, add it to a food processor or blender with the fresh basil. Blend until smooth.
Add the sauce back to the pan and cook it for an additional 5 minutes.
Turn off the heat, add the cream, parmesan cheese, and additional fresh basil.
Add drained pasta to the sauce and serve immediately.